1. Field of the Invention
The present invention relates to a cartridge adaptor mountable in a disk apparatus for reproducing or recording and reproducing a disk accommodated in a cartridge, and also to a cartridge to be accommodated in the cartridge adaptor.
2. Description of the Related Art
Along with recent improvement in the recording density of disk-shaped recording mediums such as optical disks, the resistance of such recording mediums against dust and scratches has been lowered. For the purpose of protection of the surfaces, such recording mediums are accommodated in a cartridge formed of a plastic material or the like.
A cartridge includes a case having an opening for accommodating a disk, a shutter for opening and closing the opening, and the like. Through the opening, a disk driving mechanism and a recording and reproducing head is inserted into the cartridge.
Today, optical disks are available in sizes of 3.5 inches and 5.25 inches in the field of data processing. In the audio and video field, the optical disks are available from a minimum size of 2.5 inches to a maximum size of 12 inches. Different cartridges for reproducing or recording and reproducing apparatuses are designed to receive different sizes of optical disks.
Demand for recording data in and reproducing data from different sizes of disks using one disk apparatus has been increased. Different sizes of disks, which are accommodated in different sizes of cartridges, can hardly be mounted directly in one disk apparatus. In order to mount a cartridge which is smaller than a cartridge which the disk apparatus is designed to receive, the smaller cartridge is first accommodated in a cartridge adaptor and then the cartridge adaptor is mounted in the disk apparatus. Examples of such a cartridge adaptor are disclosed in Japanese Laid-Open Patent Publication Nos. 2-121174 and 2-187973.
A conventional cartridge to be accommodated in a cartridge adaptor mainly includes a cartridge case having a head opening, a shutter for opening and closing the head opening, and an optical disk rotatably accommodated in the cartridge case. A surface of the cartridge case has a write protect tab for prohibiting erroneous deletion of data. The shutter is constantly elastically biased to close the head opening by a spring member built in the cartridge case.
A conventional cartridge adaptor mainly includes a case having a cartridge receptacle portion and a head opening and a shutter for opening and closing the head opening. In the case, an arm for opening and closing the shutter of the cartridge is pivotably supported. The arm is elastically biased by a tension spring. The case has a detection hole for, when the cartridge is accommodated in the cartridge adaptor, detecting the state of the write protect tab from outside the cartridge adaptor.
When the cartridge is inserted into the cartridge adaptor, a tip of the arm engages the shutter of the cartridge, thereby opening the shutter of the cartridge. When the cartridge adaptor is inserted into the disk apparatus, the shutter of the cartridge adaptor is opened, and the optical disk accommodated in the cartridge can be recorded or reproduced.
The cartridge and the cartridge adaptor having the above-described conventional structure has the following inconveniences.
(1) It is necessary to provide in the cartridge adaptor an arm for opening and closing the shutter of the cartridge and a shutter formed of, for example, a spring and a slider. The provision of such members are difficult due to the limited space in the cartridge adaptor and also makes the structure of the cartridge adaptor complicated. The provision of these members also limits the height of the cartridge receptacle portion since space in which the shutter is movably provided is necessary. Accordingly, the cartridge adaptor may not be able to accommodate a thick cartridge.
(2) In the case when the cartridge is inserted into the cartridge adaptor upside down, the tip of the arm does not engage the shutter of the cartridge. Then, the cartridge may undesirably be mounted in the cartridge adaptor with the shutter of the cartridge being closed. If the cartridge adaptor in such a state is inserted into the disk apparatus, the optical disk cannot be recorded or reproduced since the shutter of the cartridge is closed, and further an optical head of the disk apparatus may undesirably collide against the shutter of the cartridge and be broken.
(3) Generally, cartridges and cartridge adaptors for two-sided optical disks have an identifier for discriminating an A side from a B side of the optical disk. The identifier is detected by the disk apparatus to identify whether the current side is the A side or the B side, and thus data can be written in or read from the optical disk correctly. The above-described conventional cartridge adaptor can accommodate a cartridge even if the cartridge is inserted upside down. Accordingly, the cartridge may undesirably be mounted in the cartridge adaptor with the B side of the cartridge being on the A side of the cartridge adaptor. When this occurs, the disk apparatus detects the identifier for the A side of the cartridge adaptor and thus recognizes the current side as A, although the correct current side is B. Such an inconvenience may cause malfunction of the disk apparatus.
(4) The write protect tab for prohibiting erroneous deletion of data and the above-mentioned identifier are disposed at ends of the cartridge so that the tab and the identifier may not interfere with the optical disk accommodated in the cartridge. Accordingly, different sizes of cartridges have the tabs and the identifiers at different positions in the state of being mounted in the disk apparatus. The above-described conventional cartridge adaptor has a hole for detecting the state of the write protect tab from outside the cartridge adaptor. However, a cartridge accommodated in the cartridge adaptor has a write protect tab at a different position from the position of the write protect tab of a cartridge which the disk apparatus is designed to receive. Such an inconvenience requires provision of a mechanism in the disk apparatus for detecting the state of the write protect tab, which makes the structure of the disk apparatus complicated.